Heavy duty jack



Jan. 12, 1965 J. NOLDEN 3,165,295

HEAVY DUTY JACK Filed Dec. 14, 1962 2 Sheets-Sheet 1 J. L. NOLDEN HEAVY DUTY JACK Jan. 12, 1965 2 Sheets-Sheet 2 Filed Dec. 14, 1962 NV/J/VTOL- Ink 1. A a/den ehxw United States Patent 3,165,295 HEAVY DUTY JACK John L. Nolden, 630 Resolano Drive, Pacific Palisades, Calif. Filed Dec. 14, 1962, Ser. No. 244,620 8 Claims. ((11. 254- -2) This invention relates to a portable heavy-duty fluidoperatedindustrial hoist for lifting loads of the order of magnitude of seven tons or more and designed primarily to serve as a jack for servicing and repairing trucks of a wide range of sizes and models.

It is highly desirable that such a truck jack be compact and conveniently portable, but, above all, the truck j-ack must be strong for safe handling of loads and must have dependable safeguards against hazardous failure. In addition the truck jack must be highly flexible in the sense of being adaptable for lifting engagement in various Ways with various parts of a wide range of sizes and models of trucks. A certain problem arises in the construction of such a truck jack in that a practical compact portable fluidoperated jack necessarily has a limited lift stroke, for example, a piston stroke of 18 inches. The problem arises because in different situations the truck jack must make lifting contact with loads at widely diiferent levels. At oneextreme, the truck jack may engage the underside of a relatively high truck bed. At the other extreme, the truck may engage the bumper-supporting structure of a truck chassis at a relatively low level. Other situations require that the lift action begin at various levels intermediate these two extremes.

The problem arises because too often in employing a truck jack of the usual construction a large portion of the lift stroke is required merely to make contact with the load. For example, if 14 inches of the range of lift of 18 inches of the jack is required just to make contact with the end of a truck chassis, the truck chassis can be lifted only four inches after the contact is made.

The present invention solves this problem in part by providing a lift carriage of stepped configuration to provide a plurality of lifting shelves at different levels. The invention solves the problem in further part by making one of the shelves adjustable through a substantial range comparable to the length of the lift stroke. In the preferred practice of the invention the lowermost shelf of the carriage is adjustable and for this purpose is in the form of a separate bracket adapted for releasable engagement with the carriage at selected levels relative thereto.

In a truck jack of this general type, guide structure for the carriage extends upward from the base of the jack and since the load-engaging portion of the body of the carriage is positioned forwardly, the base extends correspondingly forward for stability. The forward position of the load-engaging portion of the carriage necessarily creates a forward tilting moment on the carriage body of high magnitude when the load is heavy and it is essential that the reaction to this high magnitude tilting moment be transmitted to the upright guide means in an effectively distributed manner Without creating undue concentration of stress in the structure of the carriage.

I Patented Jan. 12, 1965 "ice In this regard, a feature of the invention is that the body of the carriage is mounted on the piston rod in a self-adjusting manner with respect to its guiding contact with the upright gqiiding means. For this purpose the body of the carriage is provided with upper rolling means for rolling contact with the rear of the upright guide means and is provided with lower roller means for contact with the front of the upright guide means, so that with'the two roller means in simultaneous contact with the upright guide means the tilting moment of the carriage body causes equal reaction forces by the two roller means against the upright guide means. For the desired self-adjusting action, the body of the carriage is-suspended from the upper end of the piston by relatively long'tensioned means and the carriage is pivotally connected to the lower part of the tensioned means to give the carriage freedom for tilting movement as required for simultaneously equal pressure contact of the two roller means with the opposite sides of the upright guide means.

A further feature of the invention is the provision of ratchet teeth on the piston rod in combination with a safety dog or pawl that is pivotally mounted on the upper end of the power cylinder and biased into engagement with the ratchet teeth to prevent downward movement of the piston rod in the event of failure of the fluid pressure system of the jack. An important advantage of this safety arrangement is that with the ratchet teeth as close as possible to the axis of the piston rod, the stresses involved are centralized, the reaction moment having a relatively short arm.

The various features and advantages of the invention may be appreciated from the following detailed descrip tion together with the accompanying drawings.

In the drawings, which are to be regarded as merely illustrative:

FIG. 1 is a perspective view of the presently preferred embodiment of the truck jack;

FIG. 2 is a plan view of the truck jack;

FIG. 3 is a fragmentary diagrammatic elevational view illustrating the manner in which the bracket is adjusted to various levels on the carriage;

FIG. 4 is a view of the truck jack partly in side elevation and largely in section; and

FIG. 5 is a perspective view of a cross bar that may be releasably mounted on the adjustable bracket, the cross bar being equipped with adjustable load-engaging saddles.

The selected embodiment of the invention shown in the drawings has a base structure comprising a base plate 10 (FIG. 4) with upwardly extending side flanges 12 (FIG. 1) and with a forward angle iron 14 reinforced by gusset plates 15. The rear end of the base is supported by a pair of ground wheels 16 carn'edby axles 18, each axle being mounted both in the corresponding side flange 12 and in an adjacent upwardly extending car 20.

The base plate 10 has a forward circular opening 22 to provide clearance for a swiveled caster 24 which is mounted on the underside of an angular bar 25. As shown in FIGS. 1 and 4, the angular bar 25 is hingedly connected to the forward angle iron 14 and the swinging end of the angular bar is apertured to clear an upwith two ground wheels 16 to make the jack freely portable. When any substantial load is imposed on the jack, however, the spring 28 is overcometo cause the base plate to tilt downward until the forward angle iron 14 rests on the floor or ground to immobilize the jack.

' The fixed structure of the truck jack includes not only the base plate 10 but also an upright power cylinder 32 mounted on the base plate together with suitable upright fixed structure for guiding the carirage of the truck jack. I In this particular embodiment of the invention, the. guide structure comprises two upright channel members 34 that are interconnected at their upper ends by a transverse angleiron 35, the side flanges of the two channel members being turned inwardly and welded to the opposite sides of the power cylinder 32. As shown in FIG. 4, an upright pipe 36 mounted on the side of the power cylinder is connected to a port 38 at the bottom of the power cylinder 32and isadapted for connection to a suitable hose (.not shown) to receive compressed air from a suitable source.

The operating parts of the truck jack include: a cupshaped piston 40 (FIG. 4') in the power cylinder 32; a piston rod 42 that extends upward from the piston; a series of ratchet teeth 44 on the piston rod; a safety dog 45 on the upper end of the piston biased for engagement with the ratchet teeth; and a carriage mounted on the upper end of the piston rod 42.' The piston rod 42 extends through a guide collar 46 on the upper end of-the piston rod, which guide collar is'in the form of a split band with its ends 48 spaced apart (FIG. 2) to confine the safety dog 45. The safety dog 45 is mounted on a short shaft 50 that is journalled in the two band ends 48 and carries a manual release handle 52, the safety dog 45 being biased toward the ratchet teeth 44 by a torque spring 54 on the shaft. i

The vertically movable carriage of the truck jack is of stepped configuration forming three lifting shelves at three different levels, namely, an upper shelf 55, an intermediate shelf 56 and a lower shelf 58.

The upper shelf 55 of the carriage is a cross head on the upper end of the piston rod 42. The cross head may be in the form of an inverted channel iron internally reinforced by a heavy bar 60.

The intermediate shelf 56 is an integral part of a carriage body, generally designated 62, which comprises a pair of parallel spaced upright side plates 64 that are suitably interconnected for rigidity. The intermediate shelf 56 is in the form of an angle iron interconnecting the upper ends of the two side plates 64. The side plates 64 i are further interconnected by two spaced horizontal plates 65 and 66 which are cut away to clear the power cylinder 32.

The lower shelf 58 is adjustable in level relative to the carriage body 62 and'for this purpose is incorporated in aaseparate adjustable bracket-generally designated 70 of the construetion shown in FIGS. 1 andS. The bracket 70 comprises two side plates 72 that are interconnected both by a horizontal bar 74 of square cross section and by anangle iron which forms the shelf 58. The two side plates 72 of the bracket 70 slidingly straddle the carriage body 62 and-the two side plates carry inwardly directed pins 75 (FIG. 4) which slidingly engage coresponding vertical slots in the two side plates 64 of the carriage body 62. The transverse bar, 74 is at a substantially lower level thauthe two pins '75 and is adapted to seat selectively in notches 78 in the forward edges of the carriage side plates 64, the notches forming the rack teeth 80. Each of the two side plates 72 of the bracket 70 may be formed with an upper forward stopshoulder 84 for retention of loads on the bracket.

' 4 When the bracket 70 is in a selected position as shown in FIGS. 1 and 4, the two-pins75 bear against the rearwardly directed edges 82; of the vertical slots 76 and the cross bar 74 of the bracket rests one pair of rack teeth with the cross bar exerting rearward pressure on the notches in which it is seated.

It is apparent that the bracket 70 maybe changed from one level to another in the' manner indicated diagrammatically in FIG. 3. Thus when thebracket 70 is swung upward as indicated in dotted lines in FIG. 3 to move the cross bar '74 out ofengagement with therack teeth 80. the tilted bracket may be raised or lowered for seating the cross bar in a pair of notches 78 at a different level.

As shown in FIG. 5, the truck jack further includes a separate heavy cross bar 85 of square tubular cross section which in a well known manner slidingly carries a pair of saddles 86 on its opposite ends respectively. The two saddles 86 have forwardly upturned flanges 88 formed with wide notches 90 for seating the two bumper-supporting fhorns of a truck chassis. p

The cross bar 85 is suitably adapted for being removably mounted on the shelf '58 of the adjustable bracket '70. For this purpose the cross bar 85 is provided with downwardly extended ears 92 that have apertures 94. When the cross bar 85 is mounted on the .bracket 70 the cars 92 straddle the bracket and the apertures 94 of the ears register with corresponding apertures 95 in the bracket to receive a long retaining pin 96. The retaining pin 96 has a head 98 at one end and the other end is provided with asrnall diametrical bore 100 which, if desired, may receive acotter pin or the like.

A feature of the invention is the manner in which the carriage is adapted for effective selfadjustin'g engagement with the upright guide means. comprising the two-upright channel members 34. The imposition of a load on either the intermediate shelf 56 or the lower shelf58 of the carriage body 62 has the effect of tending to tilt the carriage body forward. To resist this tilting reaction to imposed loads the carriage body 62 is provided with upper roller means in sliding engagement with therearward surfaces of the two guide channels and is further provided with lower roller means'in rollingengagement with the front surfaces of the two guide channels. For this purpose each I of the two side plates 64 of the, carriage body 62 carries an' inwardly 'directedspindle' 102 journalling an upper roller 104 in contact with the rear surfaceof the corresponding guide channel 34 and carries a second lower spindle 105 journalling'a second roller 106 in contact with the front surface of the coresponding guide channel.

The self-adjusting action is provided by suitably pivotally connecting the carriage body'62 withthe upper end of the piston rod v42. For this purpose a-pair of tension members 108 is fixedly mounted by welding on the opposite ends'of the reinforced cross head that forms the upper shelf 55. In the construction shown, short laterally extending rods-110 are welded to the upper ends' of the tension members108 to serve as convenient handles for'maneuvering the truckjack. k The tension members 108 comprise metal straps which are offset as indicated at 112 in FIG. 1 to overlap the two sides of the carriage body 62. The lower end of each of the tension members 108 is interposed between'the corresponding side plate '64 of the carriage body and a metal car 114 that is welded onto the side plate. The carriage body 62 is pivotally connected to the lower ends of the two tension members 108 by pivot bolts 115, that extend through the ears and the side plates, the pivot bolts being "provided with suitable nuts 116. V

Each of the. two pivotrbolts 115 iscentralized with respect to the corresponding guide channel 34 and with respect to the ,two corresponding guide rollers 104 and 110.6. Thelocation of the two pivot boltsis such that the tilting moment applied to the carriage'body 62 by imposed loads on the shelves 56 and 58 causes the upper guide rollers 104 and the lower guide rollers 106 to press against the opposite surfaces of the upright guide channels 34 in an unrestrained manner.

A further feature of the invention is the concept of providing suitable diagonal reinforcement means to resist stresses created in the carriage body 62 by the guide rollers 104 and 106. For this purpose each upper spindle 102 that carries a corresponding upper guide roller 104 extends into a sleeve 118 and each corresponding lower spindle 105 that carries a corresponding lower roller 106 extends into a second sleeve 120, the two sleeves being in the form of cup members welded into the outer face of the corresponding side plate of the carriage body. The two cup members 118 and 120 are interconnected by a diagonal tension bar 122 that is welded both to the two cup members and to the corresponding side plate 64 of the carriage.

The manner in which the invention serves its purpose may be readily understood from the foregoing description. With the truck jack free from load, the caster 24 holds the base structure elevated from the floor and the truck jack may be readily maneuvered into any desired position by means of the two handles 110. Regardless of the height from the floor a part of a truck that is to be contacted for lifting, the truck jack may be employed with substantially the full working stroke of the jack available for elevating the truck. For example, if a relatively high stake bed of a truck is to be elevated, the upper shelf 55 of the carriage, i.e. the cross head at the top of the piston 40 is positioned under the truck bed. If a part of a truck at a somewhat lower level is to be engaged, the intermediate shelf 56 is employed. If a still lower portion of the truck is to be engaged, the bracket 70 is employed and the bracket is adjusted in height to make available substantially the full working stroke of the truck jack for elevating the truck.

The cross bar 85 with the two adjustable saddles 86 may be mounted on the bracket 70 in the previously disclosed manner. Preferably, provision is also made for releasably mounting the cross bar 85 on the intermediate shelf 56. For this purpose the two side plates 64 of the carriage 62 may be provided with upper apertures 124, which, like the previously mentioned apertures 95, are adapted to receive the retaining pin 96 for anchoring the cross bar 85 in place.

The safety dog 45 engages the ratchet teeth 44 on the piston rod 42 whenever the carriage is elevated from its lowermost position. Thus if the fluid system should fail for any reason, the carriage is maintained in elevated position by the engagement of the safety dog with a ratchet tooth. Whenever it is desired to lower the carriage, the handle 52 is manipulated to swing the safety dog 45 to a release position in opposition to the torque spring 54.

My description in specific detail of the selected embodiment of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.

I claim:

1. In a heavy duty jack of the character described, the combination of:

a portable base having two upwardly extending parallel guide members rigidly secured thereto;

an upright power cylinder mounted on the base;

a piston in the cylinder with a piston rod extending therefrom upward from the cylinder;

a carriage suspended from the upper end of said piston rod and having two interconnected side plates straddling said two guide members;

an upper rearwardly located sleeve welded to the outer side of each of said plates perpendicularly thereof;

an upper spindle mounted in each of said sleeves and extending through the side plate inwardly from the side plate;

an upper roller mounted on each of said spindles on the inner side of the side plate in rolling contact t 6 with the rear surface of the corresponding guide member;

a lower forwardly located sleeve Welded to the outer side of each of. said side plates perpendicularly thereof;

a lower spindle mounted in each of said lower sleeves and extending through the side plate inwardly from the side plate;

a lower roller mounted on each of said lower spindles on the inner side of the side plate in rolling contact with the front surface of the corresponding guide member; and

a reinforcement member on the outer surface of each side plate united with the two sleeves on the side plate and interconnecting the twosleeves in tension.

2. A combination as set forth in claim 1 in which each of said reinforcement members is welded both to the two corresponding sleeves and to the corresponding side plate.

3. In a heavy duty jack of the character described, the

combination of:

a portable base having two upwardly extending parallel guide members rigidly secured thereto;

an upright power cylinder mounted on the base;

a piston in the cylinder with a piston rod extending therefrom upward from the cylinder;

a carriage suspended from the upper end of said piston rod and having two interconnected side plates straddling said two guide members;

each of said side plates having a series of vertically spaced notches in its front edge and having a vertical slot rearward from the notches; and

a series of three steps at three successive levels to support objects to be lifted by the jack,

the highest step being a rearward step at the upper end of the piston,

the intermediate step being at the upper end of the carriage,

the lower step being a forward bracket in slidable engagement with the vertical slots and selectively engageable with said notches for vertical adjustment of the bracket.

4. A combination as set forth in claim 3 in which the upper shelf is a cross head on the upper end of the piston.

5. A combination as set forth in claim 4 which includes a pair of handles for maneuvering the jack, the handles extending laterally from the opposite sides respectively of the cross head.

6. In a heavy duty jack of the character described, the

combination of:

a portable base having two upwardly extending parallel guide members rigidly secured thereto;

an upright power cylinder mounted on the base;

a piston in the cylinder with a piston rod extending therefrom upward from the cylinder;

a carriage suspended from the upper end of said piston rod and having two interconnected side plates straddling said two guide members;

each of said side plates having a series of vertically spaced notches in its front edge and having a vertical slot rearward from the notches; and

a series of three steps at three successive levels to support objects to be lifted by the jack,

the highest step being a rearward step at the upper end of the piston,

the intermediate step being at the upper end of the carriage,

the lower step being a forward bracket in slidable engagement with the vertical slots and selectively engageable with said notches for vertical adjustment of the bracket,

said bracket having two side plates interconnected by two transverse bars, the two side plates of the bracket straddling the carriage,

one of the two bars of the bracket extending through the two slots of the side plates of the carriage,

the other .of the two bars selectively engaging the notches in the two side plates of the carriage.

7. A combination as set forth in claim 6 which further includes:

a cross bar for releasably mounting on the intermediate stepand on the lower stepselectively, said cross bar having a pair of downwardly extending apertured ears;

releasable fastening means to anchor said ears to the top of the carriage and to the bracket selectively;

and saddles adjustably mounted on the opposite ends of the cross bar for lifting engagement with loads.

' 8. A combination as set forth in claim 7 in which said releasable fastening means is a pin member,

the two sides plates of the carriage near the top of the carriage-having aligned apertures to releasably, engage the pin member,

thetwo side plates of the bracket also having aligned v.aperturesto releasably engage the pin member.

ReEer-ences Cited in the file of this patent UNITED STATES PATENTS V SheIvin Apr. 12, 1927 

1. IN A HEAVY DUTY JACK OF THE CHARACTER DESCRIBED, THE COMBINATION OF: A PORTABLE BASE HAVING TWO UPWARDLY EXTENDING PARALLEL GUIDE MEMBERS RIGIDLY SECURED THERETO; AN UPRIGHT POWER CYLINDER MOUNTED N THE BASE; A PISTON IN THE CYLINDER WITH A PISTON ROD EXTENDING THEREFROM UPWARD FROM THE CYLINDER; A CARRIAGE SUSPENDED FROM THE UPPER END OF SAID PISTON ROD AND HAVING TWO INTERCONNECTED SIDE PLATES STRADDLING SAID TWO GUIDE MEMBERS; AN UPPER REARWARDLY LOCATED SLEEVE WELDED TO THE OUTER SIDE OF EACH OF SAID PLATESA PERPENDICULARLY THEREOF; AN UPPER SPINDLE MOUNTED IN EACH OF SAID SLEEVES AND EXTENDING THROUGHT THE SIDE PLATE INWARDLY FROM THE SIDE PLATE; AN UPPER ROLLER MOUNTED ON EACH OF SAID SPINDLES ON THE INNER SIDE OF THE SIDE PLATE IN ROLLING CONTACT WITH THE REAR SURFACE OF THE CORRESPONDING GUIDE MEMBER; FIG-01 A LOWER FORWARDLY LOCATED SLEEVE WELDED TO THE OUTER SIDE OF EACH OF SAID SIDE PLATES PERPENDICULARLY THEREOF; A LOWER SPINDLE MOUNTED IN EACH OF SAID LOWER SLEEVES AND EXTENDING THROUGH THE SIDE PLATE INWARDLY FROM THE SIDE PLATE; A LOWER ROLLER MOUNTED ON EACH OF SAID LOWER SPINDLES ON THE INNER SIDE OF THE PLATE IN ROLLING CONTACT WITH THE FRONT SURFACE OF THE CORRESPONDING GUIDE MEMBER; AND A REINFORCEMENT MEMBER ON THE OUTER SURFACE OF EACH SIDE PLATE UNITED WITH THE TWO SLEEVES ON THE SIDE PLATE INTERCONNECTING THE TWO SLEEVES IN TENSION. 